Drill sharpening device



N0v..27, 1945. A 1 -M|CHELSQN 2,389,679

DRILL SHARPENING DEVICE Fiied Feb. 14. 1944 III Patented Nov. 27, 1945 UNITED STATE-s PATENT orrlce DRILL SHARPENING DEVICE Julius Michelson, West Hartford, Conn.

Application February 14, 1944, Serial N0. 522,215

3 Claims.

This invention relates to a drill sharpening xture and more particularly to a device which is adapted to hold a drill in correct position, while the point thereof is being sharpened, and to guide a sharpening member at the proper angle over said point,

It is well known that to correctly sharpen a small drill is a very diiicult operation and that even the most experienced persons iind it almost impossible to sharpen the point of such a drill so that all of the cutting edges will be evenly dis posed.

An object of this invention, therefore, is to provide a device whereby a, drill can be held in proper positions for evenly sharpening the cutting edges thereof.

A further object of the invention is toprovide such a device having means for guiding a sharpening stone at the correct angle against the end of the drill so as to form a point having cutting edges all uniformly disposed at the same angle and provided with the necessary lead by the same degree of relief in back of each cutting edge.

Further objects of the invention and advantages thereof will be more clearly understood from the following description and from the accompanying drawing in which:

Fig. 1 is a plan view of a drill sharpening device embodying my invention.

Fig. 2 is an elevational side view thereof.

Fig. 3 is a front view in central vertical section.

Fig. 4 is a sectional plan view on line 4-4 of Fig. 2.

Fig. 5 is an enlarged side view, in central vertical section, oi the upper portion of said device.

Fig. 6 is a front view of the same in central vertical section.

Fig. 7 is a further enlarged view of a portion as shown in Fig. 5,

As illustrated in the drawing, the numeral denotes the frame of my drill sharpening device,

having a base portion 6 upon which is rotatably mounted a spindle l that has secured thereto a chuck 8 having a head 9 and jaws I8.

A locating disk l I is rigidly secured tothe spindle l, to rotate therewith, and is mounted within a slot I2 in the base portion 6. The said disk is bushing I8 tting Within an opening I9 and secured therein by means of a set screw 28.

The said extension I'I is provided with a guide surface 2l which isdisposed at an angle, indicated at 22, corresponding to the angle to which the cutting edge of the drill is to be formed. The said surface is` also inclined rearwardly and curved, as indicated at 23, to correspond with the degree, or angle, of relief that is to be provided back of the cutting edge of the drill,

An adjusting screwj is threaded to the spindle I and co-axial therewith and thev saidV spindle is provided with a clamping portion 25 having a screw 26 for clamping the bottom of the chuck 8 within the recess 2l in said spindle. Y

In the operation of my invention, a drill, indicated at 28, is secured between the jaws lil of the chuck 8 and positioned therein so that it will extend through the bushing Il and project slightly above the surface 2I at the top of the device. The said drill may then be rotated to its proper position so that the cutting edge thereof will be disposed n the direction of the angle 22 of thersurface 2 I, and clamped to the spindle 'l by tightening the screw 26.y The said chuckmay then be positioned, to locate the opposite cutting edges of the drill with relation to the surface 2|, by turning the disk I I to points Where it is retained by engagement of the detent It with the corresponding one of the notches I3.

When the drill is properly positioned in said device, a sharpening stone 29, indicated in dotted lines in Fig. 6, is then moved with a reciprocatory movement against the end of the drill and over the guide surface 2l. This movement of the sharpening stone will be guided by the surface 2l so that said stone will sharpen, or form, a cutting edge and the relief, in the back of the same, as clearly shown in Fig. '7, at the correct angles.

After one side of the drill has been sharpened, the disk II is rotated and it will again be positioned by the detent lil. This will bring to sharpening position the opposite side of the drill whereupon the sharpening operation with the sharpening stone is repeated. It will be understood that the proper cutting edge has been obtained on the drill when the sharpening stone is prevented, by the guide surface 2|, from removing any more material from the end of the drill.

When both sides of the drill have been formed or sharpened, as above described, the head 9 of the chuck is turned to loosen the jaws I0 and the drill may then be removed from the device.,

In order to facilitate the removal of the drill,

the chuck 8 is provided with a passage 30 which extends through the adjusting screw 24 and the chuck 8 so that a wire, or suitable tool, may be placed therein for ejecting the drill through the top of the device.

It will be also understood that the drill may be accurately positioned to project for the correct distance above the guide surface 2| by means of the adjusting screw 24 which will position the chuck 8 in the spindle 1 before the clamping screw 26 is tightened.

The locating disk I l is preferably provided with four notches, so as to accommodate drills o r reamers having four cutting edges. Any suitable number of notches may be provided, however, to

to be sharpened in my device.

It is pointed out that my improved sharpeningA device may be adapted to drills of different sizes by the provision of a plurality of bushings I8, each having a hole therein to accommodate a certain size of drill. Said bushings may be easily interchanged by the operation ofthe set screw 20 and each of said bushings may also be properly located so that their upper ends will be correctly positioned in alignment with the surface 2l by means of a positioning surface, indicated at 3l, which cooperates with the end of the set screw 2l) when the same is forced against the said locating surface. l Y

I claim:

l. A device of the character described comprising a frame having a bearing portion, a spindle rotatably mounted in said bearing portion, locating means including an annular member secured to said spindle and rotatable therewith, a detent engageable with said locating member for positioning and retaining the same in different positions, means on said spindle for holding a drill or reamer, a guide portion on said frame, a guide surface on said guide portion disposed at the angle to which the cutting edges of said drill or reamer are to be sharpened, and means in said guide portion for positioning the end of said drill or reamer'with relation to said surface and at an intermediate point thereof.

2. A device of the character described comprising a. frame having a bearing portion with a slot extending crosswise therewith, a spindle rotatably mounted in said bearing portion and extending across said slot, a locating flange on said spindle positioned in said slot, a plurality of notches around the periphery of said flange, a detent for positioning said spindle by engagement with said notches, spring means urging said detent into such engagement, a drill holder slidably and rotatably secured to said spindle, means for clamping said drill holder to said spindle, means for slidably adjusting said tool holder in said spindle, a guide portion on said device, a bushing interchangeably secured in said guide portion and co-axial with said drill holder, and a guide surface on said guide portion for guiding a sharpening member against the end of said drill at different angles corresponding to the cutting edges of said drill and the relief back of said cutting edges.

3. A device of the character described comprising a frame having a bearing portion with a slot extending crosswise therewith, a spindle rotatably mounted in said bearing portion, a locating flange in said slot and rigidly secured to said spindle, a plurality of notches around the periphery of said flange, a detent for positioning said spindle by engagement with said notches, spring means urging said detent into such engagement, a drill holder slidably and rotatably secured to said spindle, means for clamping said drill holder to said spindle, means for slidably positioning said tool holder` in said spindle, a guide portion on said device, a bushing interchangeably secured in said guide .portion and co-axial with said drill holder, and a guide surface on said guide portion for guiding a sharpening member against the end of said drill at different angles corresponding with the cutting edges thereof and the relief back of said cutting edges; the said bushing having its upper end corresponding to the angle 0f said surface, and means for locating said bushing in said guide portion.

J ULIUS MICHELSON. 

